By means of the light field imaging it is possible to generate a spatially resolved imaging of an object, wherein the spatially resolved imaging comprises at least two images from different object planes of the object. The at least two images can typically correspond to object planes that are at a comparatively large distance from one another. By means of the light field imaging it may be possible, in particular, to generate a spatially resolved imaging, i.e. an imaging with depth information. A spatially resolved imaging is also designated as three-dimensional (3D) imaging. In the case of the spatially resolved imaging, the different images correspond to object planes that are at a distance that is greater than the depth of field of an imaging optical unit.
Light field imaging techniques are known which are based on the use of an arrangement of microlenses (microlens array), see US 2014/0263963 A1, for example. Such techniques have certain disadvantages and limitations.
By way of example, measurement data are detected which, on account of the positionally fixed arrangement of the microlenses, correspond to a scanning of the light field with fixedly predefined distances. The light field discretization induced by the scanning typically has a comparatively low spatial resolution.
Furthermore, microlenses having comparatively low Fresnel numbers can bring about additional scattering effects. This applies in particular to such objects which are situated far away from an object plane of an imaging optical unit used. This means that the physical-optical reconstruction technique used for generating the imaging of the object must typically be implemented in a comparatively complicated fashion. This can increase a requirement for computational capacities kept available or reduce an accuracy in the reconstruction.
The microlenses used typically have a comparatively long focal length. Therefore, the light field that is collected by an arrangement of microlenses cannot have a constant resolution as a function of the depth; near an image plane, in particular, the resolution can be particularly low. The focal length of a microlens cannot be reduced in a simple manner, on account of the production of the microlens.
The light field imaging by means of an arrangement of microlenses typically necessitates a detector having a large number of pixels. Therefore, in the case of the conventional light field imaging, use is typically made of detectors having a CCD sensor (charge coupled device, CCD). However, CCD sensors may have a comparatively low sensitivity, as a result of which a light intensity must be chosen to be comparatively high. That can lead to disadvantages in the case of light-sensitive samples, for example biological cell cultures. Moreover, the image quality of the spatial imaging can be decrementally affected.